高科技集群对顶尖发明人生产率的影响: 评论
The Effect of High-Tech Clusters on the Productivity of Top Inventors: Comment
American Economic Review · 2026 · [{"name": "Michael Wiebe", "affiliation": ["Oldham Council"]}]
中文摘要
Moretti（2021）报告了技术集群规模与专利产出之间的正弹性, 并运用事件研究和工具变量回归来论证其因果解释。该事件研究并未利用发明人在城市间流动所产生的变异, 且工具变量因编码错误而构造有误。我运行了修正后的事件研究并修复了该编码错误, 发现效应为零。所报告的弹性可能并非因果效应。（JEL J24, L60, O31, O34, R32）
Abstract
Moretti (2021) reports a positive elasticity between technology cluster size and patenting, and uses an event study and instrumental variables regressions to justify a causal interpretation. The event study does not use the variation generated by inventors moving across cities, and the instrument is constructed incorrectly due to a coding error. I run a corrected event study and fix the coding error, and find null effects. The reported elasticity may not be causal. (JEL J24, L60, O31, O34, R32)